The biomarker core will provide a centralized resource for the rapid and high throughput quantitation of transcripts using fluorescent real-time reverse transcriptase-eoupled quantitative PCR (Q-PCR). The use of the biomarker core will serve two fundamental purposes: 1) quantitative assessment of gene expression at the mRNA level for known genes that are involved in proliferation and implicated in cancer progression, and genes that are known markers for estrogen action in either normal or malignant endometrium and myometrium; 2) quantitative validation of the expression of genes that are initially identified in screening high density microarrays. The latter is a critical adjunct to microarray screening and will require development of a significant number of new Q-PCR assays. Specific Aims 1-3 represent interactions between projects in the SPORE and the Biomarker Core. Specific Aim 1 (Burke/Walker) Endometrial Carcinoma and SERMS. This project will examine the clinical response of women with cndometrial cancer to the SERM Arzoxifene and an important component of this will be identification of potential biomarkers of efficacy. Primary cultures of endometrial epithelial cells (normal and neoplastic) will be analyzed for changes in gene expression in response to SERMs. Total RNA will be prepared from these cells and Q-PCR will be performed using a broad panel of endometrial candidate biomarkers. In addition, novel genes identified by microarray screening in this study will be validated by Q-PCR. Specific Aim 2 (Lu/Davies) Insulin Resistance and Endometrial Cancer. This project will use a preclinical model of insulin resistance in the rat to examine biomarkers in the endometrium that are associated with the risk factors of obesity and insulin resistance. Expression of a panel of known genes will be used to initially examine endometrial response to estrogens following treatment the insulin sensitizer rosaglitazone. Additional biomarker candidates will be identified by microarray hybridization and subsequently validated by Q-PCR. The clinical arm of this study will examine candidate biomarker expression in obese, insulin-resistant post-menopausal women treated with rosaglitazone. Specific Aim 3 (Loose-Mitchell/Wolf) Molecular Progression of Endometrial Cancer. This project will identify potential biomarkers whose expression changes as cells progress from a normal phenotype, to the precancerous endometrial intraepithelial neoplasm, to hyperplasia, and to endometrial cancer. Our approach to identifying potential biomarkers will also use the 2-stage approach initially examining a panel of 33 known endometrial transcripts in the first years of the SPORE followed by microarray comparisions between the phenotypes. Newly discovered genes whose expression will is altered during the progression will be validated by Q-PCR. The predictive ability of the candidate biomarkers will be tested in women with hyperplasia treated with Megace.